From 581dd69830341d299b0c097fc366097ab497d679 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Thi=C3=A9baud=20Weksteen?= Date: Mon, 2 May 2022 10:49:52 +1000 Subject: [PATCH 1/4] firmware_loader: use kernel credentials when reading firmware MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Device drivers may decide to not load firmware when probed to avoid slowing down the boot process should the firmware filesystem not be available yet. In this case, the firmware loading request may be done when a device file associated with the driver is first accessed. The credentials of the userspace process accessing the device file may be used to validate access to the firmware files requested by the driver. Ensure that the kernel assumes the responsibility of reading the firmware. This was observed on Android for a graphic driver loading their firmware when the device file (e.g. /dev/mali0) was first opened by userspace (i.e. surfaceflinger). The security context of surfaceflinger was used to validate the access to the firmware file (e.g. /vendor/firmware/mali.bin). Previously, Android configurations were not setting up the firmware_class.path command line argument and were relying on the userspace fallback mechanism. In this case, the security context of the userspace daemon (i.e. ueventd) was consistently used to read firmware files. More Android devices are now found to set firmware_class.path which gives the kernel the opportunity to read the firmware directly (via kernel_read_file_from_path_initns). In this scenario, the current process credentials were used, even if unrelated to the loading of the firmware file. Signed-off-by: Thiébaud Weksteen Cc: # 5.10 Reviewed-by: Paul Moore Acked-by: Luis Chamberlain Link: https://lore.kernel.org/r/20220502004952.3970800-1-tweek@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/base/firmware_loader/main.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c index 94d1789a233e..406a907a4cae 100644 --- a/drivers/base/firmware_loader/main.c +++ b/drivers/base/firmware_loader/main.c @@ -735,6 +735,8 @@ _request_firmware(const struct firmware **firmware_p, const char *name, size_t offset, u32 opt_flags) { struct firmware *fw = NULL; + struct cred *kern_cred = NULL; + const struct cred *old_cred; bool nondirect = false; int ret; @@ -751,6 +753,18 @@ _request_firmware(const struct firmware **firmware_p, const char *name, if (ret <= 0) /* error or already assigned */ goto out; + /* + * We are about to try to access the firmware file. Because we may have been + * called by a driver when serving an unrelated request from userland, we use + * the kernel credentials to read the file. + */ + kern_cred = prepare_kernel_cred(NULL); + if (!kern_cred) { + ret = -ENOMEM; + goto out; + } + old_cred = override_creds(kern_cred); + ret = fw_get_filesystem_firmware(device, fw->priv, "", NULL); /* Only full reads can support decompression, platform, and sysfs. */ @@ -776,6 +790,9 @@ _request_firmware(const struct firmware **firmware_p, const char *name, } else ret = assign_fw(fw, device); + revert_creds(old_cred); + put_cred(kern_cred); + out: if (ret < 0) { fw_abort_batch_reqs(fw); From 8bf6e0e3c7de857b91a75aa57cecd56c10035bb2 Mon Sep 17 00:00:00 2001 From: Darren Hart Date: Wed, 27 Apr 2022 10:29:57 -0700 Subject: [PATCH 2/4] Documentation/process: Make groups alphabetical and use tabs consistently The list appears to be grouped by type (silicon, software, cloud) and mostly alphabetical within each group, with a few exceptions. Before adding to it, cleanup the list to be alphabetical within the groups, and use tabs consistently throughout the list. Signed-off-by: Darren Hart Link: https://lore.kernel.org/r/ec574b5d55584a3adda9bd31b7695193636ff136.1650995848.git.darren@os.amperecomputing.com Signed-off-by: Greg Kroah-Hartman --- Documentation/process/embargoed-hardware-issues.rst | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/Documentation/process/embargoed-hardware-issues.rst b/Documentation/process/embargoed-hardware-issues.rst index 6f8f36e10e8b..4f9efae02b6b 100644 --- a/Documentation/process/embargoed-hardware-issues.rst +++ b/Documentation/process/embargoed-hardware-issues.rst @@ -244,10 +244,10 @@ disclosure of a particular issue, unless requested by a response team or by an involved disclosed party. The current ambassadors list: ============= ======================================================== - ARM Grant Likely AMD Tom Lendacky - IBM Z Christian Borntraeger - IBM Power Anton Blanchard + ARM Grant Likely + IBM Power Anton Blanchard + IBM Z Christian Borntraeger Intel Tony Luck Qualcomm Trilok Soni From 29ad05fd6760c55fa7ab0e1f96e5be1b66daa4fc Mon Sep 17 00:00:00 2001 From: Darren Hart Date: Wed, 27 Apr 2022 10:29:58 -0700 Subject: [PATCH 3/4] Documentation/process: Add embargoed HW contact for Ampere Computing Add Darren Hart as Ampere Computing's ambassador for the embargoed hardware issues process. Signed-off-by: Darren Hart Link: https://lore.kernel.org/r/2e36a8e925bc958928b4afa189b2f876c392831b.1650995848.git.darren@os.amperecomputing.com Signed-off-by: Greg Kroah-Hartman --- Documentation/process/embargoed-hardware-issues.rst | 1 + 1 file changed, 1 insertion(+) diff --git a/Documentation/process/embargoed-hardware-issues.rst b/Documentation/process/embargoed-hardware-issues.rst index 4f9efae02b6b..98d7bc868f2a 100644 --- a/Documentation/process/embargoed-hardware-issues.rst +++ b/Documentation/process/embargoed-hardware-issues.rst @@ -245,6 +245,7 @@ an involved disclosed party. The current ambassadors list: ============= ======================================================== AMD Tom Lendacky + Ampere Darren Hart ARM Grant Likely IBM Power Anton Blanchard IBM Z Christian Borntraeger From 575f00edea0a7117e6a4337800ebf62e2a1d09d6 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Thu, 24 Mar 2022 15:16:05 +0000 Subject: [PATCH 4/4] Documentation/process: Update ARM contact for embargoed hardware issues With Grant taking a prominent role in Linaro, I will take over as the process ambassador for ARM w.r.t. embargoed hardware issues. Signed-off-by: Catalin Marinas Cc: Grant Likely Cc: Jonathan Corbet Signed-off-by: Jonathan Corbet Signed-off-by: Greg Kroah-Hartman --- Documentation/process/embargoed-hardware-issues.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/process/embargoed-hardware-issues.rst b/Documentation/process/embargoed-hardware-issues.rst index 98d7bc868f2a..95999302d279 100644 --- a/Documentation/process/embargoed-hardware-issues.rst +++ b/Documentation/process/embargoed-hardware-issues.rst @@ -246,7 +246,7 @@ an involved disclosed party. The current ambassadors list: ============= ======================================================== AMD Tom Lendacky Ampere Darren Hart - ARM Grant Likely + ARM Catalin Marinas IBM Power Anton Blanchard IBM Z Christian Borntraeger Intel Tony Luck